JAXA - Success! MASCOT landed safely on asteroid Ryugu

JAXA - Hayabusa2 Mission patch.

October 3, 2018

A shoebox-sized lander called the Mobile Asteroid Surface Scout (MASCOT) deployed from its mothership, Japan's Hayabusa2 spacecraft, as planned at 9:57 p.m. EDT Tuesday (Oct. 2; 0157 GMT on Oct. 3) and came to rest on Ryugu shortly thereafter.

"It could not have gone better," MASCOT project manager Tra-Mi Ho, from the DLR Institute of Space Systems in Bremen, Germany, said in a statement. (DLR is the German acronym for the German Aerospace Center, which built MASCOT in collaboration with the French space agency, CNES.

Image above: Japan's Hayabusa2 spacecraft successfully dropped the MASCOT lander on the asteroid Ryugu on Oct. 3, 2018 (Japan Standard Time). Left: Illustration of the MASCOT lander separating from the Hayabusa2 mother ship. Right: Illustration of MASCOT landing on the surface of the asteroid Ryugu. Image Credit: JAXA.

"From the lander's telemetry, we were able to see that it separated from the mothercraft and made contact with the asteroid surface approximately 20 minutes later," Ho added.

MASCOT has already started gathering data with its four onboard science instruments — a camera, a radiometer, a spectrometer and a magnetometer — mission team members said. The 22-lb. (10 kilograms) lander must make haste, because its battery is expected to die just 16 hours after touchdown.

Flight model of MASCOT. Image credit: DLR

MASCOT took 20 photos during its slow descent toward Ryugu, and these images are stored aboard Hayabusa2 at the moment, mission team members said. And observations made by the magnetometer before separation (which occurred when Hayabusa2 was about 167 feet, or 51 meters, above Ryugu) have already made it down to Earth.

"The measurements show the relatively weak field of the solar wind and the very strong magnetic disturbances caused by the spacecraft," MASCOT team member Karl-Heinz Glaßmeier, from the Technical University of Braunschweig in Germany, said in the same statement. "At the moment of the separation, we expected a clear decrease of the interference field — and we were able to recognize this clearly."

Image above: The MASCOT landing site candidate region (light blue area) on the asteroid Ryugu. Since MASCOT was expected to bounce several times after first touching down, a reasonably wide region was selected. Image Credit: AXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST, CNES, DLR.

MASCOT is following in the footsteps of MINERVA-II1A and MINERVA-II1B, two 2.4-lb. (1.1 kg) rovers that deployed from Hayabusa2 on the night of Sept. 21. Both of those little robots aced their touchdowns and soon began exploring the surface of Ryugu.

Like the Japanese-built MINERVA-II1A and MINERVA-II1B, the autonomous MASCOT can move by hopping, which it does by manipulating a metallic "swing arm" inside its body. The lander can also use this arm to right itself on Ryugu's surface — an important feature, because MASCOT needs to be right side up to gather data and beam it up to Hayabusa2.

The $150 million Hayabusa2 mission launched in December 2014 and arrived in orbit around Ryugu in late June of this year. The mothership may have one more rover deployment to go: It still carries the "optional" hopper MINERVA-II2, which could make its way to Ryugu's surface next year.

Image above: Illustration of the Hayabusa2 spacecraft. MASCOT is stored on the -Y-plane (left side) panel. Image credit： JAXA.

And the orbiter itself will make its way down to the space rock in 2019 as well, after sending a nonexplosive impactor barreling into Ryugu. Hayabusa2 will grab pristine, previously subsurface samples from the newly created crater; this material is scheduled to come down to Earth in a return capsule in December 2020.

Data gathered by the mission at Ryugu and by scientists who examine its returned sample should shed considerable light on the solar system's early history and the role that carbon-rich asteroids like Ryugu may have played in life's emergence on Earth, Hayabusa2 team members have said.

Related article:

Hayabusa2 Touches Down Ryugu:
http://orbiterchspacenews.blogspot.com/2018/09/hayabusa2-touches-down-ryugu.html

Related links:

JAXA's Hayabusa2 website: http://www.hayabusa2.jaxa.jp/en/

MASCOT website at DLR: https://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10975/

MASCOT website at CNES: https://mascot.cnes.fr/en/MASCOT/index.htm

Images (mentioned), Text, Credits: JAXA/Space.com/Mike Wall.

Best regards, Orbiter.ch

New Simulation Sheds Light on Spiraling Supermassive Black Holes

NASA Goddard Space Flight Center logo.

Oct. 2, 2018

A new model is bringing scientists a step closer to understanding the kinds of light signals produced when two supermassive black holes, which are millions to billions of times the mass of the Sun, spiral toward a collision. For the first time, a new computer simulation that fully incorporates the physical effects of Einstein’s general theory of relativity shows that gas in such systems will glow predominantly in ultraviolet and X-ray light.

Just about every galaxy the size of our own Milky Way or larger contains a monster black hole at its center. Observations show galaxy mergers occur frequently in the universe, but so far no one has seen a merger of these giant black holes.

“We know galaxies with central supermassive black holes combine all the time in the universe, yet we only see a small fraction of galaxies with two of them near their centers,” said Scott Noble, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The pairs we do see aren’t emitting strong gravitational-wave signals because they’re too far away from each other. Our goal is to identify — with light alone — even closer pairs from which gravitational-wave signals may be detected in the future.”

A paper describing the team’s analysis of the new simulation was published Tuesday, Oct. 2, in The Astrophysical Journal and is now available online.

Simulation Reveals Spiraling Supermassive Black Holes

Video above: Gas glows brightly in this computer simulation of supermassive black holes only 40 orbits from merging. Models like this may eventually help scientists pinpoint real examples of these powerful binary systems. Video Credits: NASA’s Goddard Space Flight Center.

Scientists have detected merging stellar-mass black holes — which range from around three to several dozen solar masses — using the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO). Gravitational waves are space-time ripples traveling at the speed of light. They are created when massive orbiting objects like black holes and neutron stars spiral together and merge.

Supermassive mergers will be much more difficult to find than their stellar-mass cousins. One reason ground-based observatories can’t detect gravitational waves from these events is because Earth itself is too noisy, shaking from seismic vibrations and gravitational changes from atmospheric disturbances. The detectors must be in space, like the Laser Interferometer Space Antenna (LISA) led by ESA (the European Space Agency) and planned for launch in the 2030s. Observatories monitoring sets of rapidly spinning, superdense stars called pulsars may detect gravitational waves from monster mergers. Like lighthouses, pulsars emit regularly timed beams of light that flash in and out of view as they rotate. Gravitational waves could cause slight changes in the timing of those flashes, but so far studies haven’t yielded any detections.

But supermassive binaries nearing collision may have one thing stellar-mass binaries lack — a gas-rich environment. Scientists suspect the supernova explosion that creates a stellar black hole also blows away most of the surrounding gas. The black hole consumes what little remains so quickly there isn’t much left to glow when the merger happens.

Supermassive binaries, on the other hand, result from galaxy mergers. Each supersized black hole brings along an entourage of gas and dust clouds, stars and planets. Scientists think a galaxy collision propels much of this material toward the central black holes, which consume it on a time scale similar to that needed for the binary to merge. As the black holes near, magnetic and gravitational forces heat the remaining gas, producing light astronomers should be able to see.

Animation above: This animation rotates 360 degrees around a frozen version of the simulation in the plane of the disk. Image Credits: NASA's Goddard Space Flight Center.

“It’s very important to proceed on two tracks,” said co-author Manuela Campanelli, director of the Center for Computational Relativity and Gravitation at the Rochester Institute of Technology in New York, who initiated this project nine years ago. “Modeling these events requires sophisticated computational tools that include all the physical effects produced by two supermassive black holes orbiting each other at a fraction of the speed of light. Knowing what light signals to expect from these events will help modern observations identify them. Modeling and observations will then feed into each other, helping us better understand what is happening at the hearts of most galaxies.”

The new simulation shows three orbits of a pair of supermassive black holes only 40 orbits from merging. The models reveal the light emitted at this stage of the process may be dominated by UV light with some high-energy X-rays, similar to what’s seen in any galaxy with a well-fed supermassive black hole.

Three regions of light-emitting gas glow as the black holes merge, all connected by streams of hot gas: a large ring encircling the entire system, called the circumbinary disk, and two smaller ones around each black hole, called mini disks. All these objects emit predominantly UV light. When gas flows into a mini disk at a high rate, the disk’s UV light interacts with each black hole’s corona, a region of high-energy subatomic particles above and below the disk. This interaction produces X-rays. When the accretion rate is lower, UV light dims relative to the X-rays.

Based on the simulation, the researchers expect X-rays emitted by a near-merger will be brighter and more variable than X-rays seen from single supermassive black holes. The pace of the changes links to both the orbital speed of gas located at the inner edge of the circumbinary disk as well as that of the merging black holes.

360-degree Simulated View of the Sky Between Two Supermassive Black Holes

Video above: This 360-degree video places the viewer in the middle of two circling supermassive black holes around 18.6 million miles (30 million kilometers) apart with an orbital period of 46 minutes. The simulation shows how the black holes distort the starry background and capture light, producing black hole silhouettes. A distinctive feature called a photon ring outlines the black holes. The entire system would have around 1 million times the Sun’s mass. Video Credits: NASA’s Goddard Space Flight Center; background, ESA/Gaia/DPAC.

“The way both black holes deflect light gives rise to complex lensing effects, as seen in the movie when one black hole passes in front of the other,” said Stéphane d’Ascoli, a doctoral student at École Normale Supérieure in Paris and lead author of the paper. “Some exotic features came as a surprise, such as the eyebrow-shaped shadows one black hole occasionally creates near the horizon of the other.”

The simulation ran on the National Center for Supercomputing Applications’ Blue Waters supercomputer at the University of Illinois at Urbana-Champaign. Modeling three orbits of the system took 46 days on 9,600 computing cores. Campanelli said the collaboration was recently awarded additional time on Blue Waters to continue developing their models.

 Blue Waters Supercomputer. Image Credit: University of Illinois

The original simulation estimated gas temperatures. The team plans to refine their code to model how changing parameters of the system, like temperature, distance, total mass and accretion rate, will affect the emitted light. They’re interested in seeing what happens to gas traveling between the two black holes as well as modeling longer time spans.

“We need to find signals in the light from supermassive black hole binaries distinctive enough that astronomers can find these rare systems among the throng of bright single supermassive black holes,” said co-author Julian Krolik, an astrophysicist at Johns Hopkins University in Baltimore. “If we can do that, we might be able to discover merging supermassive black holes before they’re seen by a space-based gravitational-wave observatory.”

Related links:

The Astrophysical Journal: https://doi.org/10.3847/1538-4357/aad8b4

Laser Interferometer Gravitational-Wave Observatory (LIGO): https://www.ligo.caltech.edu/

Laser Interferometer Space Antenna (LISA): https://lisa.nasa.gov/

Center for Computational Relativity and Gravitation: https://ccrg.rit.edu/

Rochester Institute of Technology: https://www.rit.edu/

European Space Agency (ESA): https://www.esa.int/ESA

École Normale Supérieure de Paris: http://www.ens.fr/en

National Center for Supercomputing Applications: http://www.ncsa.illinois.edu/

Blue Waters supercomputer: http://www.ncsa.illinois.edu/enabling/bluewaters

University of Illinois at Urbana-Champaign: https://illinois.edu/

Johns Hopkins University: https://www.jhu.edu/

NASA’s Goddard Space Flight Center: https://www.nasa.gov/goddard

High-Tech Computing: https://www.nasa.gov/topics/technology/high-tech-computing/index.html

Black Holes: https://www.nasa.gov/black-holes

Animation (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Jeanette Kazmierczak.

Greetings, Orbiter.ch

October Starts With Crew Swap Then Spacewalks

ISS - Expedition 56 Mission patch.

October 2, 2018

October will be a busy month as a pair of crews get ready to swap places on the International Space Station followed by a pair of spacewalks. Also, Japan’s HTV-7 resupply ship is open for business and the Expedition 56 crew has begun unloading its science and supplies.

Station commander Drew Feustel is preparing to return to Earth Thursday with two of his crewmates despite a busy schedule of science and maintenance aboard the orbital lab. Cosmonaut Oleg Artemyev is packing the Soyuz MS-08 spacecraft today that he will pilot back to Earth flanked by Feustel and NASA astronaut Ricky Arnold. The trio is due to land in Kazakhstan at 7:45 a.m. after 197 days in space.

Image above: (From left) Expedition 56 Commander Drew Feustel of NASA and Soyuz MS-08 Commander Oleg Artemyev of Roscosmos practice on a computer the Soyuz descent procedures they will use when they return to Earth on Oct. 4. Image Credit: NASA.

Expedition 57 starts when the Soyuz MS-08 crew ship undocks Thursday at 3:57 a.m. EDT. Staying behind are Alexander Gerst of ESA (European Space Agency) who will command the station with Flight Engineers Serena Auñón-Chancellor and Sergey Prokopyev until a new pair of crewmates join the following week.

NASA astronaut Nick Hague and Soyuz Commander Alexey Ovchinin will blast off Oct. 11 at 4:40 a.m. aboard the Soyuz MS-10 crew ship and take a six hour ride to their new home in space. The duo is in Kazakhstan at the Baikonur Cosmodrome launch site making final preparations for their 187 day mission.

International Space Station (ISS)

The station is being replenished today as the crew begins offloading cargo from the HTV-7 resupply ship from JAXA (Japan Aerospace Exploration Agency). Robotics controllers will soon unload new lithion-ion batteries packed inside HTV-7 and install them on the truss structure to upgrade the station’s power systems. A pair of spacewalks are planned before the end of the month to complete the battery connections.

Related article:

Japan’s Kounotori Spaceship Attached to Station:
http://orbiterchspacenews.blogspot.com/2018/09/japans-kounotori-spaceship-attached-to.html

Related links:

Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

JAXA (Japan Aerospace Exploration Agency): http://global.jaxa.jp/projects/iss_human/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation, Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

NASA’s OSIRIS-REx Executes First Asteroid Approach Maneuver

NASA - OSIRIS-REx Mission patch.

Oct. 2, 2018

NASA’s OSIRIS-REx spacecraft executed its first Asteroid Approach Maneuver (AAM-1) today putting it on course for its scheduled arrival at the asteroid Bennu in December. The spacecraft’s main engine thrusters fired in a braking maneuver designed to slow the spacecraft’s speed relative to Bennu from approximately 1,100 mph (491 m/sec) to 313 mph (140 m/sec). The mission team will continue to examine telemetry and tracking data as they become available and will have more information on the results of the maneuver over the next week.

Image above: Illustration of NASA’s OSIRIS-REx spacecraft during a burn of its main engine. Image Credit: University of Arizona.

During the next six weeks, the OSIRIS-REx spacecraft will continue executing the series of asteroid approach maneuvers designed to fly the spacecraft through a precise corridor during its final slow approach to Bennu. The last of these, AAM-4, scheduled for Nov. 12, will adjust the spacecraft’s trajectory to arrive at a position 12 miles (20 km) from Bennu on Dec. 3. After arrival, the spacecraft will initiate asteroid proximity operations by performing a series of fly-bys over Bennu’s poles and equator.

OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security Regolith Explorer): http://www.nasa.gov/mission_pages/osiris-rex/index.html

Image (mentioned), Text, Credits: NASA/Rob Garner/GSFC/Nancy N. Jones/University of Arizona/Erin Morton.

Greetings, Orbiter.ch

Gaia spots stars flying between galaxies

ESA - Gaia Mission patch.

2 October 2018

A team of astronomers using the latest set of data from ESA’s Gaia mission to look for high-velocity stars being kicked out of the Milky Way were surprised to find stars instead sprinting inwards – perhaps from another galaxy.

In April, ESA’s stellar surveyor Gaia released an unprecedented catalogue of more than one billion stars. Astronomers across the world have been working ceaselessly over the past few months to explore this extraordinary dataset, scrutinising the properties and motions of stars in our Galaxy and beyond with never before achieved precision, giving rise to a multitude of new and intriguing studies..

Sprinting stars in the Milky Way

The Milky Way contains over a hundred billion stars. Most are located in a disc with a dense, bulging centre, at the middle of which is a supermassive black hole. The rest are spread out in a much larger spherical halo.

Stars circle around the Milky Way at hundreds of kilometres per second, and their motions contain a wealth of information about the past history of the Galaxy. The fastest class of stars in our Galaxy are called hypervelocity stars, which are thought to start their life near the Galactic centre to be later flung towards the edge of the Milky Way via interactions with the black hole.

Only a small number of hypervelocity stars have ever been discovered, and Gaia’s recently published second data release provides a unique opportunity to look for more of them.

Several groups of astronomers jumped into the brand-new dataset in search of hypervelocity stars immediately after the release. Among them, three scientists at Leiden University, the Netherlands, were in for a big surprise.

For 1.3 billion stars, Gaia measured positions, parallaxes – an indicator of their distance – and 2D motions on the plane of the sky. For seven million of the brightest ones, it also measured how quickly they move towards or away from us.

All-sky view from Gaia's second data release

“Of the seven million Gaia stars with full 3D velocity measurements, we found twenty that could be travelling fast enough to eventually escape from the Milky Way,” explains Elena Maria Rossi, one of the authors of the new study.

Elena and colleagues, who had already discovered a handful of hypervelocity stars last year in an exploratory study based on data from Gaia's first release, were pleasantly surprised, as they were hoping to find at most one star breaking loose from the Galaxy among these seven million. And there is more.

“Rather than flying away from the Galactic centre, most of the high velocity stars we spotted seem to be racing towards it,” adds co-author Tommaso Marchetti.

“These could be stars from another galaxy, zooming right through the Milky Way.”

It is possible that these intergalactic interlopers come from the Large Magellanic Cloud, a relatively small galaxy orbiting the Milky Way, or they may originate from a galaxy even further afield.

If that is the case, they carry the imprint of their site of origin, and studying them at much closer distances than their parent galaxy could provide unprecedented information on the nature of stars in another galaxy – similar in a way to studying martian material brought to our planet by meteorites.

Large Magellanic Cloud

“Stars can be accelerated to high velocities when they interact with a supermassive black hole,” Elena explains.

“So the presence of these stars might be a sign of such black holes in nearby galaxies. But the stars may also have once been part of a binary system, flung towards the Milky Way when their companion star exploded as a supernova. Either way, studying them could tell us more about these kinds of processes in nearby galaxies.”

An alternative explanation is that the newly identified sprinting stars could be native to our Galaxy’s halo, accelerated and pushed inwards through interactions with one of the dwarf galaxies that fell towards the Milky Way during its build-up history. Additional information about the age and composition of the stars could help the astronomers clarify their origin.

“A star from the Milky Way halo is likely to be fairly old and mostly made of hydrogen, whereas stars from other galaxies could contain lots of heavier elements,” says Tommaso.

“Looking at the colours of stars tells us more about what they are made of.”

Gaia mapping the Milky Way

New data will help nail down the nature and origin of these stars with more certainty, and the team will use ground-based telescopes to find out more about them. In the meantime, Gaia continues to make observations of the full sky, including the stars analysed in this study.

While investigating the nature of these possible stellar interlopers, the team is also busy digging into the full dataset from Gaia’s second release, searching for more high-speed stars and looking forward to the future. At least two more Gaia data releases are planned in the 2020s, and each will provide both more precise and new information on a larger set of stars.

“We eventually expect full 3D velocity measurements for up to 150 million stars,” explains co-author Anthony Brown, chair of the Gaia Data Processing and Analysis Consortium Executive.

“This will help find hundreds or thousands of hypervelocity stars, understand their origin in much more detail, and use them to investigate the Galactic centre environment as well as the history of our Galaxy,” he adds.

“This exciting result shows that Gaia is a true discovery machine, providing the ground for completely unexpected discoveries about our Galaxy,” concludes Timo Prusti, Gaia project scientist at ESA.

Notes for editors:

“Gaia DR2 in 6D: Searching for the fastest stars in the Galaxy” by T. Marchetti et al is published in Monthly Notices of the Royal Astronomical Society: https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/sty2592/5104415

Related link:

Gaia: http://www.esa.int/Our_Activities/Space_Science/Gaia

Related article:

Counting stars with Gaia: https://orbiterchspacenews.blogspot.com/2015/07/counting-stars-with-gaia.html

Gaia's first year of scientific observations: https://orbiterchspacenews.blogspot.com/2015/08/gaias-first-year-of-scientific.html

The billion-pixel camera:
https://orbiterchspacenews.blogspot.com/2011/07/eye-of-gaia-billion-pixel-camera-to-map.html

Images, Text, Credits: ESA (artist’s impression and composition); Marchetti et al 2018 (star positions and trajectories); NASA/ESA/Hubble (background galaxies), CC BY-SA 3.0 IGO/ESA/Gaia/DPAC/ATG medialab; background: ESO/S. Brunier.

Best regards, Orbiter.ch

ISOLDE reveals shape-shifting character of Mercury isotopes

CERN - European Organization for Nuclear Research logo.

1 Oct 2018

An unprecedented combination of experimental nuclear physics and theoretical and computational modelling techniques has been brought together to reveal the full extent of the odd-even shape staggering of exotic mercury isotopes, and explain how it happens. The result, from an international team at the ISOLDE nuclear physics facility at CERN, published today in Nature Physics, demonstrates and explains a phenomenon unique to mercury isotopes where the shape of the atomic nuclei dramatically moves between a football and rugby ball.

Isotopes are forms of an element that contain the same number of protons in their nuclei but different numbers of neutrons. The properties of different isotopes can be exploited in a variety of ways including archaeological and historical dating (Carbon 14) and medical diagnostics.  Stable isotopes have an optimal ratio of protons to neutrons.  However, as the number of neutrons decreases or increases, structural changes to the nucleus are required and the isotope typically becomes unstable.  This means it will spontaneously transform itself towards a stable isotope of another element through radioactive decay.  Isotopes with extreme neutron to proton ratios are typically very short-lived, making them difficult to produce and study in the laboratory. ISOLDE is the only place in the world that can study such a wide range of exotic isotopes.

Lasers at ISOLDE. RILIS experiment (Image: Noemi Caraban/CERN)

One of the earliest experiments in the ISOLDE facility observed dramatic nuclear shape staggering in the chain of mercury isotopes for the first time.  That more than 40 year old result showed that although most of the isotopes with neutron numbers between 96 and 136 have spherical nuclei, those with 101, 103 and 105 neutrons have strongly elongated nuclei, the shape of rugby balls.  That discovery has remained one of ISOLDE’s flagship results, but it was so dramatic that it was difficult to believe.

In this new result, the experimental team used laser ionisation spectroscopy, mass spectrometry and nuclear spectroscopy techniques to take a closer look at how, why and when these quantum phase transitions take place.  Not only did the team reproduce the results of the historic experiment (observing isotopes up to Mercury 181), by producing and studying four additional exotic isotopes (177- 180), it also discovered the point at which the shape staggering ceases and mercury isotopes return to normal isotope behaviour.   Several theories had tried to describe what was happening, but none was able to provide a full explanation.

“Due to the extreme difficulty in producing such exotic nuclei, as well as the computational challenge of modelling such a complex system, the reasons for this shape staggering phenomenon remained unclear,” explains Bruce Marsh.  “It is only now, with new developments of ISOLDE’s Resonance Ionisation Laser Ion Source (RILIS), and by joining forces with other ISOLDE teams, that we have been able to examine the nuclear structure of these isotopes.”

These experimental observations were in themselves outstanding, but the collaboration wanted to conclude the story by explaining the shape staggering effect theoretically.  Using one of the world’s most powerful supercomputers, theorists in Japan performed the most ambitious nuclear shell model calculations to date.

These calculations identified the microscopic components that drive the shape shifting; specifically, that four protons are excited beyond a level predicted by expectations of how other stable isotopes in the nuclear landscape behave.  These four protons combine with eight neutrons and this drives the shift to the elongated nuclear shape.  In fact, both nuclear shapes are possible for each mercury isotope, depending on whether it is in the ground or excited state, but most have a football shaped nucleus in their ground state.  The surprise is that Nature chooses the elongated rugby ball shape as the ground state for three of the isotopes.

“Ingenuity and innovation are characteristics of the ISOLDE community and the generation and measurement of the suite of mercury isotopes is a particularly beautiful example,” said Eckhard Elsen, CERN’s Director for Research and Computing.  “I am even more impressed that the theoretical explanation of the puzzling behaviour using supercomputer modelling was provided at the same time.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

ISOLDE: http://home.cern/about/experiments/isolde

Nature Physics: http://dx.doi.org/10.1038/s41567-018-0292-8

For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/

Image (mentioned), Text, Credits: CERN/Corinne Pralavorio.

Greetings, Orbiter.ch

A Universe Aglow

ESO - European Southern Observatory logo.

1 October 2018

MUSE spectrograph reveals that nearly the entire sky in the early Universe is glowing with Lyman-alpha emission

A Universe Aglow

Deep observations made with the MUSE spectrograph on ESO’s Very Large Telescope have uncovered vast cosmic reservoirs of atomic hydrogen surrounding distant galaxies. The exquisite sensitivity of MUSE allowed for direct observations of dim clouds of hydrogen glowing with Lyman-alpha emission in the early Universe — revealing that almost the whole night sky is invisibly aglow.

An unexpected abundance of Lyman-alpha emission in the Hubble Ultra Deep Field (HUDF) region was discovered by an international team of astronomers using the MUSE instrument on ESO’s Very Large Telescope (VLT). The discovered emission covers nearly the entire field of view — leading the team to extrapolate that almost all of the sky is invisibly glowing with Lyman-alpha emission from the early Universe [1].

Digitized Sky Survey image around the Hubble ultra Deep Field

Astronomers have long been accustomed to the sky looking wildly different at different wavelengths, but the extent of the observed Lyman-alpha emission was still surprising. “Realising that the whole sky glows in optical when observing the Lyman-alpha emission from distant clouds of hydrogen was a literally eye-opening surprise,” explained Kasper Borello Schmidt, a member of the team of astronomers behind this result.

“This is a great discovery!” added team member Themiya Nanayakkara. “Next time you look at the moonless night sky and see the stars, imagine the unseen glow of hydrogen: the first building block of the universe, illuminating the whole night sky.”

The Hubble Ultra Deep Field in the constellation of Fornax

The HUDF region the team observed is an otherwise unremarkable area in the constellation of Fornax (the Furnace), which was famously mapped by the NASA/ESA Hubble Space Telescope in 2004, when Hubble spent more than 270 hours of precious observing time looking deeper than ever before into this region of space.

The HUDF observations revealed thousands of galaxies scattered across what appeared to be a dark patch of sky, giving us a humbling view of the scale of the Universe. Now, the outstanding capabilities of MUSE have allowed us to peer even deeper. The detection of Lyman-alpha emission in the HUDF is the first time astronomers have been able to see this faint emission from the gaseous envelopes of the earliest galaxies. This composite image shows the Lyman-alpha radiation in blue superimposed on the iconic HUDF image.

MUSE, the instrument behind these latest observations, is a state-of-the-art integral field spectrograph installed on Unit Telescope 4 of the VLT at ESO’s Paranal Observatory [2]. When MUSE observes the sky, it sees the distribution of wavelengths in the light striking every pixel in its detector. Looking at the full spectrum of light from astronomical objects provides us with deep insights into the astrophysical processes occurring in the Universe [3].

"With these MUSE observations, we get a completely new view on the diffuse gas 'cocoons' that surround galaxies in the early Universe," commented Philipp Richter, another member of the team.

ESOcast 178 Light: A Universe Aglow

The international team of astronomers who made these observations have tentatively identified what is causing these distant clouds of hydrogen to emit Lyman-alpha, but the precise cause remains a mystery. However, as this faint omnipresent glow is thought to be ubiquitous in the night sky, future research is expected to shed light on its origin.

“In the future, we plan to make even more sensitive measurements,” concluded Lutz Wisotzki, leader of the team. “We want to find out the details of how these vast cosmic reservoirs of atomic hydrogen are distributed in space.”

Notes:

[1] Light travels astonishingly quickly, but at a finite speed, meaning that the light reaching Earth from extremely distant galaxies took a long time to travel, giving us a window to the past, when the Universe was much younger.

[2] Unit Telescope 4 of the VLT, Yepun, hosts a suite of exceptional scientific instruments and technologically advanced systems, including the Adaptive Optics Facility, which was recently awarded the 2018 Paul F. Forman Team Engineering Excellence Award by the American Optical Society.

[3] The Lyman-alpha radiation that MUSE observed originates from atomic electron transitions in hydrogen atoms which radiate light with a wavelength of around 122 nanometres. As such, this radiation is fully absorbed by the Earth’s atmosphere. Only red-shifted Lyman-alpha emission from extremely distant galaxies has a long enough wavelength to pass through Earth’s atmosphere unimpeded and be detected using ESO’s ground-based telescopes.

More information:

This research was presented in a paper titled “Nearly 100% of the sky is covered by Lyman-α emission around high redshift galaxies” which was published today in the journal Nature.

The team is composed of Lutz Wisotzki (Leibniz-Institut für Astrophysik Potsdam, Germany), Roland Bacon (CRAL - CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, Université de Lyon, France), Jarle Brinchmann (Universiteit Leiden, the Netherlands; Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Portugal), Sebastiano Cantalupo (ETH Zürich, Switzerland), Philipp Richter (Universität Potsdam, Germany), Joop Schaye (Universiteit Leiden, the Netherlands), Kasper B. Schmidt (Leibniz-Institut für Astrophysik Potsdam, Germany), Tanya Urrutia (Leibniz-Institut für Astrophysik Potsdam, Germany), Peter M. Weilbacher (Leibniz-Institut für Astrophysik Potsdam, Germany), Mohammad Akhlaghi (CRAL - CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, Université de Lyon, France), Nicolas Bouché (Université de Toulouse, France), Thierry Contini (Université de Toulouse, France), Bruno Guiderdoni (CRAL - CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, L’Université de Lyon, France), Edmund C. Herenz (Stockholms universitet, Sweden), Hanae Inami (L’Université de Lyon, France), Josephine Kerutt (Leibniz-Institut für Astrophysik Potsdam, Germany), Floriane Leclercq (CRAL - CNRS, Université Claude Bernard Lyon 1, ENS de Lyon,L’Université de Lyon, France), Raffaella A. Marino (ETH Zürich, Switzerland), Michael Maseda (Universiteit Leiden, the Netherlands), Ana Monreal-Ibero (Instituto Astrofísica de Canarias, Spain; Universidad de La Laguna, Spain), Themiya Nanayakkara (Universiteit Leiden, the Netherlands), Johan Richard (CRAL - CNRS, Université Claude Bernard Lyon 1, ENS de Lyon,L’Université de Lyon, France), Rikke Saust (Leibniz-Institut für Astrophysik Potsdam, Germany), Matthias Steinmetz (Leibniz-Institut für Astrophysik Potsdam, Germany), and Martin Wendt (Universität Potsdam, Germany).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a strategic partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

Links:

Photos of MUSE: https://www.eso.org/public/images/archive/search/?subject_name=MUSE

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

MUSE instrument: https://www.eso.org/public/teles-instr/paranal-observatory/vlt/vlt-instr/muse/

Very Large Telescope (VLT): https://www.eso.org/public/teles-instr/paranal-observatory/vlt/

Adaptive Optics Facility: https://www.eso.org/public/blog/adaptive-optics-facility/

ESO’s Paranal Observatory: https://www.eso.org/public/teles-instr/paranal-observatory/

NASA/ESA Hubble Space Telescope: https://www.spacetelescope.org/

Images, Text, Credits: ESO/Calum Turner/MUSE Principal Investigator / Lyon Centre for Astrophysics Research (CRAL)/Roland Bacon/Leibniz-Institut für Astrophysik Potsdam/Lutz Wisotzki/ESA/Hubble & NASA, ESO/ Lutz Wisotzki et al./ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin/IAU and Sky & Telescope/Video: ESO, F. Kamphues, Digitized Sky Survey 2, Lutz Wisotzki et al, MUSE Consortium, R. Bacon and J. Pérez.

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